Circuit breaker



June 1, 1937. R, H, SCHMlTT 2,082,660

CIRCUJT BREAKER Filed June 27, 1935` 2 Sheets-Sheet 1 Invehtor: Richard I-l. Schm itt.

I iis Attorney.

June l, 1937. R. H. SCHMITT CIRCUIT BREAKER Filed June 27, 1935 2 simens-sheetv 2 Inventor: a Richard H. Schmitt,

HIS Attornfg.

Patented June 1, 1937 UNITED STATES CIRCUIT BREAKER Richard H. Schmitt, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application June 27, 1935, Serial No. 28,617 12 caimsf (o1. 20c-116) My invention relates to circuit breakers, more particularly to circuit breakers of the trip-free type in which the circuit controlling contacts are manually operable to open and close the circuit, and are automatically operable to open the circuit on the occurrence of predetermined current conditions, independently of the manual operating means, and has for an object the provision of a simple, reliable and inexpensive circuit breaker of this character.

Various overload circuit breakers of this type have heretofore been proposed, all of which are more or less satisfactory. Some diiliculty, however, has been encountered in connection with small circuit breakers of this type, due tothe fact that under certain conditions the contacts of the circuit breaker may stick together so tightly that the operating mechanism is incapable of exerting suii'lcient force to cause separation of the contacts. Much is yet to be desired in an' inexpensive and reliable circuit breaker of small size for use as a motor starting switch and accordingly, it is a further object of my invention to provide a simple and inexpensive circuit breaker of this character in which a sharp hammer blow is imparted to the contacts in order to operate them to the open circuit position either manually or upon the occurrence of predetermined current conditions.

In carrying 'out my invention in one form, I provide a circuit breaker comprising movable switch means normally biasedl to a closed circuit position, and manually operable means for im-` f parting a hammer blow to the switch means to operate the switch means to open circuit position against the bias thereof. Current responsive means are also provided for imparting a hammer blow to the switch means to open the circuit independently of the manual means upon the occurrence of predetermined current conditions.

More specically, I provide a multi-pole, double-break circuit breaker comprising a plurality of bridging members arranged within suitable cavities in the circuit breaker base,the walls of the cavities serving to guide the bridging members for reciprocal movement. Abuttingly engaging each of the bridging members is a compresposition. This manual means is also operable with a snap action to another position to permit the biasing springs to return the bridging members to the closed circuit position. Also arranged adjacent the sldable member, I provide a tripping 5 member biased for movement towards the sldable member and normally latched in spaced relation thereto by current responsive means releasable upon the occurrence of predetermined current conditions to permit .the tripping member to strike 10 the sldable member a hammer blow and operate the bridging members to the open circuit position.'

For a more complete understanding of my invention, reference should now be had to the drawings in which Fig. 161s a plan view of a circuit 15 breaker embodying my invention; Fig. 2 is a scctional, elevational view taken along the line 2-2 of Fig, 1; Fig. 3 is a sectional, elevational view taken along the line 3-3 of .'Flg. 1; Fig. 4 is a vsectional view taken along the line 4 4 of Fig. 1; 2-0

Fig. 5 is an exploded perspective view on a somewhat reduced scale of the circuit breaker shown in Figs. 1 to 4 inclusive; and Figs. 6, "l, and 8 are somewhat diagrammatic views illustrating the circuit breaker parts in various operating 25 positions. g

Referring now to Figs. 1 to 5 inclusive of thev drawings, I have shown my invention as embodied in a multi-pole, double-break circuit breaker comprising a base member III formed of molded 30 insulating material provided with a pair oaf'recesses II and I2. Adjacent one end of the base I0 is an insulating block I3 which is adapted to be secured to the base I0 and which is provided with a similar pair of recesses 'I4 and I5 which 35 cooperate with the recesses II and I2 respectively to form cavities within which the contacts of the circuit breaker are arranged.

As shown best in Fig. 2, the circuit breaker `contacts within the cavity formed by the cooper- 40 guide the bridging member for reciprocal movement between open and closed circuit positions, and a compression spring 23 serving to bias the bridging member to the closed circuit position.

The circuit breaker contacts which constitute the other pole of the circuit breaker are arranged in the cavity formed by the recesses I2 and I5 and 55 are identical with the arrangement just described, except that the ixed contact corresponding to the iixed contact i1 is mounted on a conductor 24` (Fig. 1) which is secured to a terminal screw 25 connected in series circuit relation with the helical resistance heater element of a current responsive device 26, the heater element in turn being connected to a terminal 21. The same reference numerals will be used throughout to identity corresponding contacts in the two cavities. As shown, the current responsive device 26 is of a suitable fusible metal or solder type in which a ratchet wheel is normally retained against movement by the solder and is released for rotation by fusion of the solder upon the-occurrence of predetermined current conditions, such as disclosed in my copending application Serial No. 673,636, led May 31, 1933.

Arranged intermediate the recesses 'ii and i2 in the base, I provide a freely movable member 28 slidably supported on guides 29 formed integrally with the base. As shown best in Fig. 5, the slidable member 28 extends through a wall of each of the cavities in the base and is provided with laterally extending portions 30 arranged abuttingly to engage the bridging members 22,

^ the slidable member 26 being biased to the position shown in Figs. 1 to 4 inclusive by this abutting engagement with the bridging members.

In order to insure that the circuit breaker contacts will be positively operated to the open circuit position regardless of any slight welding or sticking between the contacts,-I provide means for imparting a hammer blow to the slidable member 28 so as to operate the contacts to the open circuit position against the bias exerted by the springs 23. As shown, the operating mechanism of the circuit breaker is supported on an elongate plate 3i which is secured to the circuit breaker base by suitable screws 32 and 33 (Fig. 3), the screw 33 extending through the insulating block I3 and serving to secure the block i3 to the base I0.

Intermediate its ends the supporting plate 3i is provided with an aperture 34 and a pair oi laterally extending parallel portions 35 and 36, each of the portions 35 and 36 being bifurcated, as shown, to provide stops for an operating link 31.` As shown, the link 31 comprises a hollow rectangular iramelike structure which encircles the extending portions 35 and 36, one side of the link 31 pivotally engaging notches 38 formed in the portions 35 and36.

Pivotally mounted on a pin 39 carried by the supporting plate 3| and extending across the aperture 34 in the supporting plate, is a handle member 40 provided with an operating finger 4i and a resetting finger 42. As shown best in Fig. 3, the operating linger 4i pivotally supports an abutment member 43 which engages one end of an overcenter compression lspring 44, the other end of which engages the operating link 31. It will be apparent that when the handle 40 is moved downwardly, as viewed in the drawings, from the position shown in Fig. 3, the operating finger 4i will move into the aperture in the link 31 and will carry the lower end of the spring 44 overcenter relative to the `pivot point of the link 31 whereupon the spring 44 will operate the link 31 with a snap action from the position shown in Fig. 3 to the position shown in Fig. 5 in which position the link 31 engages theother of the two stops formed by the bifurcated ends of the portions 35 and 36. During this movement, it will be apparent that the operating link 31 will en- `6, 7, and 8.

gage a shoulder as` (Fig. 3) on the slidable member 28 to impart a hammer blow thereto and move the slidable member so as to operate the bridging members 22 to the open circuit position.

In order to provide for automatic opening of the circuit breaker in response to predetermined current conditions, I provide a tripping member comprising a li-shaped member 46, the legs of which are pivotally supported on the pin 3B and the yoke portion of which supports a pair ,of members 41 made of a suitable insulating material, such as iibrc. Secured between the adjacent ends of the insulating members 41 opposite from the member 46 is a detent member 48, a laterally extending portion 49 of which is arranged to engage the ratchet wheel of the current responsve device 26. Another portion of the detent 48 `is engaged by a biasing spring 50, the other end of which is secured to a rivet 5i in the base l0.

It will be apparent that the spring 5U biases the tripping member for movement in a counterclockwise direction about the pivot pin 39 toward. the slidable member 28, and that the detent portion 49 and the current responsive device 26 normally retain the tripping member in the position shown in Fig. 3 in spaced relation to the slidable member 23. Upon the occurrence oi such predetermined current conditions as would cause the ratchet wheel of the current responsive device 26 to be released for movement, the spring 56 will quickly rotate the tripping member in a counter-clockwise direction about its pivot 39 to strike a shoulder portion 52 on f the slidable member 28 a hammerlike blow and operate ,the bridging members 22 to the open circuit position against the biasing iorce exerted by the springs 23.

. In order to provide for resetting the' tripping member after an operation thereof to open the contacts of the circuit breaker, the U-shaped member 46 is provided with an extending portion 53 (Figs. 3 and 5) arranged to be engaged by the resetting iinger 42 on the operating handle 48. It will be apparent that after automatic operation to the open position, when the operating handle '40 is rotated in a clockwise direction from the position shown in Fig. 3, the resetting finger 42 engages the portion 53 of the4 reset member to return the reset member to the position shown in Fig. 3 in which position the detent finger 49 will again engage the ratchet wheel of the current responsive device 26. In order ericctively to insulate the heater coil of the curreni i responsive device 26 from the operating mechanism of the circuit breaker, I provide an insulating. barrier 54 which is supported in suitable slots in the base I0 and in the insulating block I3.

The operation of the circuit breaker will now be described with particular reference to Figs. In Fig. 6, the circuit breaker is shown in the closed circuit position which position is also shown in Figs. l to 4 inclusive. In order to operate the circuit breaker to the open circuit position, the handle member 40 isv rotated in a clockwise direction about its pivot, as viewed in Figs. 2 and 3, and the operating link 31 will thereupon be moved with a snap action, as heretofore described, to the position shown in Fig. 8, the operating link 31 during this movement striking the shoulder 45 on the slidable member 28 a. hammer like blow and operating the bridging members 22 to the open circuit position shown in Fig. 8 against the biasing force exerted by the springs 23. In order to reclose the circuit breaker, the operating handle 40 is returned to the position shown in Figs. 2 and 3 and the operating link 31 will thereupon be moved with a snap action to the position shown in Fig. 6 so as to release the slidable member 28 and the bridging members 22 for movement to the closed circuit position shown in Fig. 6 in accordance with the v b1as exerted by the springs 23. It will, of course,

u, overload current iiows through the circuit breaker. Upon the occurrence of such a predetermined current condition, the heating winding of the current responsive device 26 will produce sumcient heat to fuse the solder normally holding the ratchet wheel of the device 26 against movement whereupon the force exerted by the spring 50 will cause the ratchet wheel to rotate in a counter-clockwise direction, as viewed'in Figs. 6, 7, and 8, and release the tripping member 46 for movement in accordance with the force exerted by the spring 5I) to the position shown in Fig. 7. During this movement, the tripping member 46 will strike the portion 52 of the slidable member 28 a hammerlike blow and will move the slidable member 28 soas to operate the bridging members 22 to the open circuit position shown in Fig. 7 against the force exerted by the springs 23, the force exerted by the spring 50 being suflicient to maintain the bridging members in this open circuit position against the i'orce exerted by the springs 23.

It will be apparent that operation of'the tripl ping member 46 to the position shown in Fig. 7

will have no eifect upon the position of the manually operablet handle member 40 and in order to reclose the'circuit breaker after an automatic operation, it is'necessary to move the handle from the on position shown in Figs. 2 and 3 to the off this movement of the handle 40, the reset nger 42 carried thereby will engage the portion 53 extending from the tripping member 46 as hereinbefore described so as to return the tripping member 46 from the position shown in Fig. 7 to the position shown in Fig. 8, the operating link 31 during this movementj'of the handle 40 snapping to the position shown in Fig. 8 so as to maintain the contacts in the open circuit position. It will be apparent that if the current responsive device 26 has cooled suiciently by this time so that the ratchet wheel is restrained against rotation, the ratchet wheel and the detent 49 will cooperate to retain the tripping member 46 in the position shown in Fig. 8, and the circuit breaker may be reclosed by moving the operating handle 40- to the on position shown in Figs. 2 and 3, the operating link `3l snapping to the position shown in Fig. 6 to permit the slidable member 28 and the bridging members 22 to be returned to the position shown in. Fig. 6 by the biasing springs 23.

It will be apparent that the cavities formed by the cooperating recesses II, I2, I4 and I5 constitute housings for the circuit breaker contacts within which the arc incident to the interruption of the circuit through the circuit breaker is Y coniined. The slidable member 23 moves through position shown in Fig. 5. Duringan aperture in one wall of each housing and substantially closes theapertures during circuit interrupting movement of the contacts.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as i'all within the true spirit and scope of my invention.

4 What I claim as new and desire to secure by Letters Patent in the United States is:

1. A circuit breaker comprising movable switch means constantly biased toward closed circuit position, means manually operable to one position for striking said switch means a hammer blow to operate said switch means to open circuit position against the bias thereon, said manual means being operable to a second position to permit movement of said switch means to said closed circuit position in accordance with the bias thereon, and current responsive means for striking said switch means a hammer blowto operate said switch means to said open circuit position independently of said manual'means upon the occurrence of predetermined current conditions.

2. A circuit breaker comprising-movable switch means constantly biased toward closed circuit position, means manually operable to one position for striking said switch means a hammer blow to operate said switch means to open circuit position against vthe bias thereon, said manual means being operable to a second position to permit movement of said switch means to said closedl circuit position in accordance with the bias thereon, current responsive means operable from "a normal position upon the occurrence of predetermined current conditions for striking said switch means a hammer blow to operate said switch means to said open circuit position independently ofk said manual means, and means operable by said manual means for returning said current responsive means to said normal position.

3. A circuit breaker comprising movable switch means, spring means for constantly biasing said switch means toward closed circuit position, means operable between two positions with a snap action, manual means for operating saidl snap means to one of said two positions to strike said switch means a hammer blow and operate said switch means to open circuit position against the bias of said spring means, said manual means also being eiective to operate said snap means to the other of said two positions to permit operation of said switch means to said closed circuit position by said spring means, and current responsive means operable upony the occurrencel of predetermined current conditions for striking said switch means a hammer blow to operate said switch means to said open circuit position independently of said snap means.

4. A circuit breaker comprising movable switch means constantly biased toward closed circuit position, a plurality oi operating members positioned adjacent said switch means,` manual means for quickly actuating one of said operating members from one position to a second position to strike said switch means a hammer blow and operate said switch means to open circuit position, said manual means being arranged to retain said operating member in said second position against the bias on said switch means, said manual means also being operable to return said operating member to said one position to permit operation of said switch means to said closed circuit position in accordance with the bias thereon, and current responsive means for actuating another of said operating members to strike said switch means a hammer blow and operate said switch means to said open circuit position indel pendently of said manual means.

5. A circuit breaker comprising a movable switch member constantly biased toward closed circuit position, a freely movable member biased to a normal position by abutting engagement with said switch member, means manually operable to one position for striking said movable member to operate said switch member to open circuit position with a hammer blow, said manual means being operable to another position to permit movement of said switch member to said closed circuit position in accordance with its bias, whereby said freely movable member is returned to said normal position, and current responsive means operable upon the occurrence of predetermined current conditions for striking said movable member to operate said switch member to said open circuit position with a hammer blow independently of said manually operable means.

6. A circuit breaker comprising a movable switch member constantly biased toward closed circuit position, a freely movable member biased to a normal position by abutting engagement with said switch member, means operable with a snapactlon to one position for striking said movable member to operate said switch member to open circuit position with a hammer blow, said snap acting means being operable to another po sitionto permit movement of said switch member to said closed circuit position in accordance with its bias, whereby said freely movable member is returned to said normal position, current responsive means operable upon the occurrence of predetermined current conditions for striking said movable member to operate said switch member to said open circuit position with a hammer blow independently of said snap acting means, and means operable jointly with said snap acting means i or resetting said current responsive means. i

7. A circuit breaker comprising a movabl switch member normally biased to closed circuit position, a freely slidable member normally biased to one position by abutting engagement with said switch means, a plurality of operating members adjacent said slidable members, means for moving one of said operating members between on and off position with a snap action, said one operating member during movement to said off position striking said slidable member a hammer blow quickly to operate said switch member to open circuit position against its bias, movement of said one operating member to said on position permitting operation of said switch member and said slidable member to said respective biased positions, means for biasing another of said operating members for movement toward said slidable member, and current responsive means normally latching said other operating member and releasable to permit movement of said other operating member by said biasing means to strike said slidable member a hammer blow and operate said switch member to said open circuit position.

8. A circuit breaker comprising a movable switch member normally biased to closed circuit position, a freely movable slidable member normally biased to one position by abutting engagement with said switch member, means operable toward said slidable member with a snap action for striking said slidable member a hammer blow quickly to move said slidable member and thereby quickly operate said switch member to an open circuit position, said striking means being operable away from said slidable member with a snap action to release said slidable member whereupon said switch member is quickly operated to said closed circuited position in accordance with its bias, a movable tripping member normally biased for movement toward said slidable member, means for latching said tripping member in spaced relation to said slidable member, and current responsive means for releasing said latching means whereupon said tripping member is operated in accordance with its bias t'o strike said slidable member a hammer blow and quickly operate said switch member to its open circuit position.

9. A circuit breaker comprising an insulating base having a recess therein, an insulating block adapted to be secured to said base andrhaving a recess therein cooperating with said recess in said base to form a cavity, a movable switch member within said cavity supported and guided solely by the side walls of the cavity, spring means arranged between said switch member and an end wall of said cavity for biasing said switch member to one of two positions, and means extending through the opposite end wall of said cavityfor abuttingly engaging said switch member to move said switch member to the other or said two positions against the bias of said spring means.

10. A circuit breaker comprising an insulating base having a recess therein, a ilxed contact supported in said recess, an insulating block having a cooperating recess therein, a fixed contact supported in said cooperating recess,means for securing said block on said base, said re cesses cooperating to form a cavity having spaced apart fixed contacts therein, a movable bridging member arranged within saidv cavity supported and guided solely by engagement with the walls thereof, spring means arranged between said bridging member and a wall of said cavity for biasing said bridging member into engagement with `said fixed contacts, and means extending through an aperture in another wall of` said cavity for abuttingly engaging said bridging member to move said bridging member out of engagement with said fixed contacts.

11. A circuit breaker comprising walls of insulating material arranged to form a housing, a movable switch member within said housing supported and guided solely by said walls, spring means arranged between one of said walls and said switch member for biasing said switch member to closed circuit position, a freely movable member slidably extending through an aperture in one of said walls for abuttingly engaging said switch member, means manually operable to one position for striking said .slidable member to operate said switch member to open circuit position with a hammer blow, said manual means being operable to another position to permit movement of said switch member to said closed circuit position in accordance with its bias, and current responsive means operable upon the oc currence of predetermined current conditions for striking said slidable member to operate said switch member to said open circuit position with a hammer blow independently of said manually operable means. i

12. A circuit breaker comprising an insulating base having a recess therein, a iixed contact supported in said recess, an insulating block having a, vcooperating recess therein, a xed contact supported in said cooperating recess, means for securing said block on said base, said recesses cooperating to form a cavity having spaced apart iixed contacts therein, a movable bridglng member within said cavity supported and guided solely by engagement -with the walls thereof, spring means arranged between said bridging member and a wall of, said cavity for biasing said bridgingv member to a closed circuit position in which said bridging member engages said Iixed contacts, a freely movable member slidably extending through another wall of said cavity and biased to one position by abutting engagement with said bridging member, means supported on said base adjacent said other wall of said cavity operable towards the extending end of said slidable vmember with a snap action for striking said slidable member a hammer blow to move said slidable member and thereby quickly operate said bridging' member to open circuit position, said striking means being operable away from said slidable member with a snap action to permit said biasing spring to operate said bridging member to said closed cir-l cuit position, a movable tripping member normally biased for movement toward said slidable member,- means for latching said tripping mem- 

